Single cell protein: Meeting the protein gap and enabling sustainable aquaculture

To bridge the feed protein gap, the aquaculture industry needs to diversify its raw material basket with novel ingredients that have lower environmental footprints and optimum nutritional values. One of these novel ingredients is single cell protein (SCP), which is produced by fermenting microorganisms such as bacteria, yeast, or algae using renewable feedstocks.

Dr. Louise Buttle
Sustell™ Lead for Aqua & Global Key Account Manager
dsm-firmenich

Aquaculture is the fastest growing food sector in the world, providing nutritious and affordable animal protein to millions of people. However, in order to grow sustainably, within planetary boundaries, an important driver is the supply of sustainable raw materials.

Traditionally fish meal from forage fisheries or trimmings have been used in aquaculture and supply a high-quality protein source although in recent years the level of inclusion has dropped. Accordingly, the supply of fish meal is finite and subject to fluctuations in availability due to variations in the environment. One current example is the impact on the Peruvian fishery due to El Nino weather phenomenon. Soy protein concentrate is an example of a widely used plant-based protein source, and even though has excellent nutritional properties its production has questions over land use, water use, and greenhouse gas emissions.

To bridge the feed protein gap, the aquaculture industry needs to diversify its raw material basket with novel ingredients that have lower environmental footprints and optimum nutritional values. One of these novel ingredients is single cell protein (SCP), which is produced by fermenting microorganisms such as bacteria, yeast, or algae using renewable feedstocks.

Single cell protein has several advantages over conventional protein sources. First, it has a consistently high protein content (up to 70%) and a balanced amino acid profile that meets the nutritional requirements of various aquaculture species. Second, single cell protein has a low environmental impact, as it does not require arable land, freshwater, or marine resources, and it can utilize waste streams as substrates. Third, it has a high scalability potential, as it can be produced in large volumes using bioreactors that can be located in geographical regions of the world close to aquaculture farming centres.

While single cell protein is not a new concept, having been used for human and animal nutrition since the 1960s, recent advances in biotechnology have enabled the development of more efficient and cost-effective production processes that can compete with traditional protein sources.

Figure 1. Proof of concept trial in Rainbow trout trial; fish fed from 50g to 300g (12 weeks). A dose response trial, where single cell protein was included from 0 to 20% of the formulation.

SALMONID FEEDING TRIAL RESULTS
Early prototypes of a single cell protein produced by researchers at the DSM Bioscience Centre in Delft, The Netherlands showed excellent performance comparable to feeds containing fish meal and soy protein concentrate. Rainbow trout were grown for 12 weeks on different inclusions of SCP ranging from 0%, 5%, 10% to 20% on extruded feeds, with single cell protein replacing a combination of fish meal and soy protein concentrate. The data is shown in Figure 1, indicating that single cell protein inclusion has no negative impact on fish performance measured by final body weight.

Single cell protein is not only a sustainable solution for aquaculture, livestock and companion animal feed, but also a potential driver for decarbonization and circular economy. Single cell protein production can be powered by renewable energy sources such as solar, wind, or biogas, and it can capture and convert carbon dioxide into biomass.

Single cell protein is one of the key innovations that can help the aquaculture industry achieve its sustainability goals, such as science-based targets (https://sciencebasedtargets.org/) and contribute to global food security. Single cell protein production has the potential to be net zero for the aquaculture industry in terms of carbon emissions and resource usage. This means that its production does not contribute to the increase of greenhouse gas emissions or consume a significant amount of non-renewable resources.

Whilst aquaculture feeds have reduced their dependency on marine ingredients from fisheries and trimmings there is still a significant reliance on soy protein. Availability of novel raw materials rich in protein would bring with it stability of supply and economics as the aquaculture industry grows. If the production of novel protein raw materials at scale with market conditions was easy, we would have these technologies available today. It will take industry-wide commitment and capital investment, possibly co-investment by stakeholders to make this a reality. Collaborating across the value chain is key to drive the continued sustainable production of aquaculture, every member of the value chain has a role to make this happen and enable production at scale of single cell protein.

About Dr. Louise Buttle
Dr. Louise Buttle is an aquaculture professional with over 25 years’ experience in the industry. After completing a PhD at the University of Hull on the physiology of nitrogen excretion in the African catfish, Dr. Buttle joined EWOS Cargill. Whilst employed by EWOS Cargill, Buttle held various roles in R&D, product development and sustainability in global teams for the business in Scotland, Chile and Norway. Working in these salmon countries also provided Louise Buttle with a unique perspective and experience of the salmon industry. Today, Dr. Buttle is working in the Global Aqua team for DSM with technical marketing and has commercial Global Key Account Responsibility in ANH Essential products. Buttle has a strong passion for sustainable development of aquaculture and is leading the business roll out of Sustell™ in the Aquaculture Industry.